Filet Knife question

[Buzzkill]

I've had a request for a filet knife, which is far thinner and more flexible than anything I've made to this point.  While I consider it beyond anything I can reasonably accomplish right now, I'm wondering if anyone who has forged a filet knife can suggest a good steel for the project so I can get some practice materials.   I'm fairly sure the heat treat is critical to get the desired results, but I don't want to start with a steel which doesn't lend itself well to a thin and flexible blade.

If you have pics I'd love to see those as well.

[Steve Sells]

I use L-6

[Frosty]

Old blacksmith wisdom, "forge it thick, grind it thin."

Frosty The Lucky.

[Michael Cochran]

One way to do it would be to make friends wth a carpenter so you can get his used sawzall blades. They are thin and flexible so you'd just have to grind off the teeth and procede with a stock removal knife project. I wouldn't buy one just for this project because the cost is more than a little ridiculous just to ruin a good blade.

[TacticallySharp]

I've made a couple a few years back. Used Aldo's 1084. When I blue backed them I found that to get the flex I had to take it to gray. They are still in service and I haven't gotten one back.

[Buzzkill]

Thanks for the responses.

Based on what I see for the heat treat on L6 it's out of the question.  I probably should have added that I don't have any equipment to accurately hold temperature or raise/lower temps in steps over time.  So far I haven't done anything more difficult than O1.   I guess there's always the option to send out for heat treating, but I prefer to do everything myself if I can.

I'm a little surprised that the 1084 could get the needed flex and still have decent edge retention, but I may have to give that a shot.

 

[gearhartironwerks]

You have to start thinking about the usage of the knife being in water and rust because of that. L6 saw blade rusts easily. Most fishermen don't care for their blades as a chef would.

My suggestion would be to buy a stainless blade and handle it. I know this is anathema for this site and bladesmithing, but unless you have experience with stainless blades, you may want to consider it.

John

[Buzzkill]

Good point John.  It makes me wonder if I could forge some stainless san mai that thin and get the best of both worlds. It's a bit on the expensive side for experimenting though...

Anyone ever try that in a filet knife?

[BIGGUNDOCTOR]

Mr. Howell , a custom knife maker back home made his fillet knives out of ATS34 stainless. He showed me a completed one, put the tip against the tabletop, and pushed the handle down so that the blade made a 90°. When he let up the blade snapped right back. He said he loved it for that application. He claimed a 60 C hardness. They were his only production knife, and he sold dozens to the fishermen in the Pacific Northwest.

[bigfootnampa]

I haven't forged a filet knife yet.  I do use them though and I am very picky about them!  I have reground blades to get the proper flex.  I agree with Frosty that grinding is the key!  The blades that I like are smooth tapered in both directions, width and thickness.  I also like them with long shallow bevels that are very slightly convex.  I have made pretty poor blades into excellent filet knives by regrinding the tapers and bevels.  This is a much better way to adjust flex than by altering the heat treatment!  Stainless is good but not necessary IMO as a filet knife of mine will always be treated quite carefully.  you can actually get better performance from non-stainless in some cases.  A good commercial example is the Browning filet knives!  Take a look at them in your sporting goods store.  They are tapered just about right!  You really want a pretty hard blade as it will need to cut through bones like they were wax!  if you mess with the heat treat to get more flex you'll end with too soft steel!  The distal taper is tricky as it needs to be quite subtle and yet become pretty thin towards the tip.  The taper in width is fairly easy by comparison as you can judge it by eye fairly easily.  Sneak up on it, testing the flex as you go, until you have it just about right.  Keep your bevels roughly ground as you work it down, or you'll overshoot and end with too much flex after you grind in the bevels... this is especially important at the tip as the bevels there can represent a significant portion of the steel cross section.

Commonly I will get the flex close to what I want and make the final refinements mostly by grinding the spine of the blades!  This avoids the need to constantly regrind the bevels!  I generally round the spines of the blades over a little, making them easier to make tight turning cuts with... which are needed at certain stages!

[Steve Sells]

11 hours ago, gearhartironwerks said:

You have to start thinking about the usage of the knife being in water and rust because of that. L6 saw blade rusts easily. Most fishermen don't care for their blades as a chef would.

I didnt think of the lack of care part, My blades are not cheap, so very few people willing to pay (like a Chef) would leave them laying around wet.   For a  budget maybe Jantz or USA knifemaker blanks would make sense, since its stock removal not forging and you get properly heat treated stainless.

[JHCC]

1 hour ago, Steve Sells said:

I didnt think of the lack of care part, My blades are not cheap, so very few people willing to pay (like a Chef) would leave them laying around wet.   For a  budget maybe Jantz or USA knifemaker blanks would make sense, since its stock removal not forging and you get properly heat treated stainless.

I suppose it also depends on whether the end user is a chef or a fisherman and in what conditions the knife will be used and stored.